An optical semiconductor component, typically a laser diode (LD) or a photodiode (PD), is contained in an optical semiconductor component package for both protection and for electrical connection to an external signal wire, or for optical connection to an external optical fiber. Light emitted from the optical semiconductor component may be unintendedly reflected by, for example, members in the optical semiconductor component package, and the reflected light may be received by a light-receiving element as stray light.
A semiconductor light-emitting element described in Japanese Patent Application Publication No. 2002-26439 includes a semiconductor light chip mounting base with a rough front surface, which is coated with a light absorbing film to reduce stray light resulting from its return light. The semiconductor light-emitting element described in Japanese Patent Application Publication No. 2002-26439 has the relatively small front surface of the base to reduce stray light, and may not reduce stray light unless light returns to the front of the base.